Bulbospongiosus Research Articles

Long-term assessment of effectiveness and quality of life of OnabotulinumtoxinA injections in provoked vestibulodynia.

Provoked vestibulodynia is a relatively common condition that affects sexual activity. Multidisciplinary care is indicated and OnabotulinumtoxinA injections are safe and effective treatment in this indication. To assess the long-term efficacy of OnabotulinumtoxinA in provoked vestibulodynia. Twenty-one patients treated with OnabotulinumtoxinA injections (50U in each bulbospongiosus muscle) 24 months prior to the study were included. Data on pain [assessed using a visual analogue scale (VAS)], quality of life [measured by the Dermatology Life Quality Index (DLQI)] and quality of sex life [assessed using the Female Sexual Function Index (FSFI)] were collected before treatment, and 3 and 24 months after injection. Nineteen patients participated in the study and 37% had no pain after 24 months. Significant improvements were noted in the VAS, DLQI and FSFI scores between baseline and 24 months post treatment (P < 0.0001). After 24 months, 18 patients (95%) were able to have sexual intercourse. This study was open and non-controlled. 100U OnabotulinumtoxinA injections constitute an effective treatment in provoked vestibulodynia with results maintained after 2 years. They significantly improve pain, and have a positive impact on patient quality of life and sex life. Beneficial effects continue in the long-term, allowing patients to resume sexual activity.

Perineal Neurophysiological Assessment in 23 Patients Suffering from Persistent Genital Arousal Disorders: Evidence of Pudendal Neuropathy?

ABSTRACTObjectives: Persistent genital arousal disorder (PGAD) is a rare condition. Our aim was to study whether or not the pudendal nerve is involved in PGAD, by means of electromyographic (EMG) testing. Methods: Twenty-three women who fulfilled the five criteria of PGAD were included in this study. After an in-depth interview and routine investigations, a perineal EMG assessment was performed. Concentric needle electromyography (EMG) testing with motor unit potential analysis of the pelvic floor muscles (bulbocavernosus muscle and striated external anal sphincter), study of the sacral reflex latency (SRL), and measurement of pudendal nerve terminal motor latency (PNTML) were performed. Results: Perineal ENMG demonstrated neurogenic changes in 14 (60.8%) of the patients. Denervation was found in all 14 patients with abnormal electrophysiological findings. Among them, 12 (85.7%) had altered PTNML and/or SRL. PTNML was delayed on the anal branch in 9 out of 14 (bilateral in 5 cases) and on the perineal branch in 9 out of 14 (bilateral in 6 cases). Conclusions: This study shows that pudendal neuropathy is frequent among women suffering from PGAD. However, due to the lack of a control group, involvement of pudendal neuropathy in the pathogenesis of PGAD remains unclear.

Aromatase expression is linked to estrogenic sensitivity of periurethral muscles in female rabbits.

Beyond its role in the conversion of androgens to estrogens, the expression of aromatase could influence on the estrogenic signalling in targeted tissues. Considering the well-defined biochemical and physiological differences between the pubococcygeus (Pcm) and bulbospongiosus (Bsm) muscles in female rabbits, it is presently hypothesized that the aromatase expression is differentially linked to the estrogen sensitivity of each muscle. To this end, serum estradiol levels and the aromatase expression, presence of ERα and ERβ and morphometry were evaluated in the Pcm and Bsm of female rabbits allocated in control, ovariectomized (OVX) and OVX treated with estradiol benzoate (OVX + EB) groups. Aromatase expression was high in the Pcm. Independently to serum estradiol, ovariectomy increased aromatase expression in the Pcm while decreased it in the Bsm. The EB treatment avoided the effect of ovariectomy only in the Pcm. The number of immunoreactive nuclei anti-ERα and anti-ERβ was high in the Pcm of OVX and OVX + EB rabbits, while those in the Bsm remained unchanged. The number of peripheral nuclei per fibre and the cross-sectional area-to-myonucleus ratio were modified only in the Pcm. Our findings support aromatase expression in the Pcm, and Bsm of rabbits is differentially linked to estrogenic sensitivity of each muscle.

MP51-13 BULBOCAVERNOSUS MUSCLE AREA AS A MARKER OF ANDROGENIZATION

You have accessJournal of UrologySexual Function/Dysfunction/Andrology: Evaluation II1 Apr 2015MP51-13 BULBOCAVERNOSUS MUSCLE AREA AS A MARKER OF ANDROGENIZATION Nikhil Gupta, Amin Herati, Yuki Yamashita, and Bruce Gilbert Nikhil GuptaNikhil Gupta More articles by this author , Amin HeratiAmin Herati More articles by this author , Yuki YamashitaYuki Yamashita More articles by this author , and Bruce GilbertBruce Gilbert More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1750AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Treatment for hypogonadal symptoms is often essential to improve quality of life. However, traditional diagnostic tools, symptoms and serum testosterone level (T), often fail to identify men who would benefit from therapy. New markers may identify men of equivocal hypogonadal status who should receive T replacement. Studies have shown that the Bulbocavernosus Muscle (BCM) is androgen sensitive. Dabaja et al (Asian J Androl, 16:1-5, 2014) demonstrated that the BCM area is directly related to androgen receptor activity. Castration reduces the BCM area and androgen replacement increases BCM area in animal studies. This study investigates whether a relationship exists between BCM area serum testosterone and Luteinizing Hormone levels (LH) in a symptomatic male population. METHODS Men presenting with symptoms of hypogonadism underwent standard evaluation including a measurement of BCM area using B-mode perineal ultrasonography. Men with previous androgen treatment were excluded. Morning T (LH/MS) and LH levels were compared with BCM area to investigate a correlation between LH/testosterone and BCM area and BCM area normalized for body mass index (BMI). RESULTS Forty-three men presenting for erectile dysfunction, hypogonadism symptoms or infertility had both BCM area on ultrasound and morning T and LH levels. A correlation was found between T level and both BCM area and normalized BCM area with a T cutoff of 400 ng/dL. Below T of 400 ng/dL BCM area averaged 0.54 cm2, while above T of 400 ng/dL BCM area averaged 0.72 cm2. A correlation was also found between BCM area and LH level at a cutoff of 3 IU/L. Below LH 3 IU/L, BCM area averaged 0.71 cm2 and with LH above 3 IU/L BCM area averaged 0.56 cm2. No correlation was found between normalized BCM area and LH at this level. CONCLUSIONS Normal and low BCM area as measured by ultrasound correlate with T and LH levels. T < 400 ng/dl and LH > 3 IU/L correlate with decreased BCM area while T > 400 ng/dl and LH < 3 IU/L correlate with a normal BCM area. Thus BCM area appears to be a clinical marker of androgenization and can be useful, particularly in men with equivocal serum testosterone values, to identify those that might benefit from androgen supplementation. T < 400 T > 400 p LH < 3 LH > 3 p Age 54.3 54.1 0.98 49.7 55.0 0.34 BMI 29.6 25.8 0.03 26.4 29.6 0.10 BCM 0.54 0.72 0.02 0.71 0.56 0.03 Normalized BCM 0.02 0.03 0.01 0.02 0.02 0.13 © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e624 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nikhil Gupta More articles by this author Amin Herati More articles by this author Yuki Yamashita More articles by this author Bruce Gilbert More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Activation of mu or delta opioid receptors in the lumbosacral spinal cord is essential for ejaculatory reflexes in male rats.

Ejaculation is controlled by a spinal ejaculation generator located in the lumbosacral spinal cord, consisting in male rats of lumbar spinothalamic (LSt) cells and their inter-spinal projections to autonomic and motor centers. LSt cells co-express several neuropeptides, including gastrin releasing peptide (GRP) and enkephalin. We previously demonstrated in rats that GRP regulates ejaculation by acting within the lumbosacral spinal cord. In the present study, the hypothesis was tested that enkephalin controls ejaculation by acting on mu (MOR) or delta opioid receptors (DOR) in LSt target areas. Adult male rats were anesthetized and spinalized and received intrathecal infusions of vehicle, MOR antagonist CTOP (0.4 or 4 nmol), DOR antagonist (TIPP (0.4, 4 or 40 nmol), MOR agonist DAMGO (0.1 or 10 nmol), or DOR agonist deltorphin II (1.3 or 13 nmol). Ejaculatory reflexes were triggered by stimulation of the dorsal penile nerve (DPN) and seminal vesicle pressure and rhythmic contractions of the bulbocavernosus muscle were analyzed. Intrathecal infusion of MOR or DOR antagonists effectively blocked ejaculatory reflexes induced by DPN stimulation. Intrathecal infusion of DAMGO, but not deltorphin II triggered ejaculation in absence of DPN stimulation. Both MOR and DOR agonists facilitated ejaculatory reflexes induced by subthreshold DPN stimulation in all animals. Overall, these results support the hypothesis that enkephalin plays a critical role in the control of ejaculation in male rats. Activation of either MOR or DOR in LSt target areas is required for ejaculation, while MOR activation is sufficient to trigger ejaculation in the absence of sensory stimulation.

Pudendal Nerve and Internal Pudendal Artery Damage May Contribute to Radiation-Induced Erectile Dysfunction

Erectile dysfunction is common after radiation therapy for prostate cancer; yet, the etiopathology of radiation-induced erectile dysfunction (RI-ED) remains poorly understood. A novel animal model was developed to study RI-ED, wherein stereotactic body radiation therapy (SBRT) was used to irradiate the prostate, neurovascular bundles (NVB), and penile bulb (PB) of dogs. The purpose was to describe vascular and neurogenic injuries after the irradiation of only the NVB or the PB, and after irradiation of all 3 sites (prostate, NVB, and PB) with varying doses of radiation. Dogs were treated with 50, 40, or 30 Gy to the prostate, NVB, and PB, or 50 Gy to either the NVB or the PB, by 5-fraction SBRT. Electrophysiologic studies of the pudendal nerve and bulbospongiosus muscles and ultrasound studies of pelvic perfusion were performed before and after SBRT. The results of these bioassays were correlated with histopathologic changes. SBRT caused slowing of the systolic rise time, which corresponded to decreased arterial patency. Alterations in the response of the internal pudendal artery to vasoactive drugs were observed, wherein SBRT caused a paradoxical response to papaverine, slowing the systolic rise time after 40 and 50 Gy; these changes appeared to have some dose dependency. The neurofilament content of penile nerves was also decreased at high doses and was more profound when the PB was irradiated than when the NVB was irradiated. These findings are coincident with slowing of motor nerve conduction velocities in the pudendal nerve after SBRT. This is the first report in which prostatic irradiation was shown to cause morphologic arterial damage that was coincident with altered internal pudendal arterial tone, and in which decreased motor function in the pudendal nerve was attributed to axonal degeneration and loss. Further investigation of the role played by damage to these structures in RI-ED is warranted.

Chapter 3 - Anatomy and physiology of genital organs – men

Male sexual functions involve a number of organs and structures in genitalia whose role is to produce fertilizing gametes and to allow female-partner insemination. The testes belong to the reproductive and endocrine systems as they synthesize spermatozoa and androgens, and are under finely regulated hormonal control by the hypothalamopituitary axis. Sexual responses are controlled by a complex and coordinated interplay of both the somatic and the autonomic nervous system in multiple components of the brain, spinal cord, and relevant peripheral organs. Erectile bodies are an essential element of the penis and engorgement of the penis with blood leads to penile tumescence. Blood engorgement is due to relaxation of smooth-muscle cells of erectile tissue and endothelium of the penile arteries. The penis gains additional rigidity when the ischiocavernosus muscles contract. Stimuli from peripheral and/or central origins activate particular spinal nuclei, causing penile erection. Ejaculation consists of two phases, emission and expulsion, which correspond, respectively, to secretion of the different components of the semen by sex glands and forceful expulsion of semen due to rhythmic contractions of the bulbospongiosus muscle. A spinal generator of ejaculation integrates genital stimuli and sexual cues and, when the excitatory threshold is reached, triggers ejaculation by orchestrating the activation of autonomic and somatic pathways commanding the peripheral events of ejaculation.

Reliability of Superficial Male Pelvic Floor Structural Measurements Using Linear-Array Transperineal Sonography

This study evaluated reliability of measures for superficial structures of the male pelvic floor (PF) obtained via transperineal sonography. Two embalmed cadavers were dissected to identify positioning of muscles on and around the bulb of the penis and to confirm the PF protocol. Cross-sectional area (CSA) and linear thickness of the bulb of the penis, urethra, bulbospongiosus (BS) muscles, and ischiocavernosus (IC) muscles were measured on 38 transverse images from 20 male patients by three raters with varied study knowledge and sonographic experience. Intra- and inter-rater reliability were calculated with two-way, mixed effects intra-class correlation coefficients. Measures of the bulb of the penis had the best reliability. CSA of all muscles and sagittal thickness of the BS near the central tendon had good reliability. Reliability varied for rater-identified thickest muscle region and measures of the urethra. Our study suggests that structures of the male PF can be reliably evaluated using a transperineal sonographic approach.

The Male Bulbospongiosus Muscle and its Relation to the External Anal Sphincter

The bulbospongiosus muscle is part of the superficial muscular layer of the perineum and pelvic floor. Its morphology remains controversial in the literature. Therefore, we reinvestigated the fascial arrangement and fiber courses of the bulbospongiosus muscle and its topographical relation to the external anal sphincter. The perineum was dissected in 9 male cadavers (mean ± SD age 78.3 ± 10.7 years). Select samples were obtained for histology and immunohistochemistry. In 43 patients (mean age 60.7 ± 12 years) the topographical relation between the bulbospongiosus muscle and the external anal sphincter was determined by magnetic resonance imaging. The perineum contains several fascial layers consisting of elastic and collagen fibers as well as bundles of smooth muscle cells. The bulbospongiosus muscle was subdivided into a ventral and dorsal portion, which developed in 4 variants. The ventral insertion formed a morphological unity with the ischiocavernous muscle while the dorsal origin had a variable relation to the external anal sphincter (5 variants). A muscle-like or connective tissue-like connection was frequently present between the muscles. However, in some cases the muscles were completely separated. We suggest a concept of variations of bulbospongiosus muscle morphology that unifies the conflicting literature. Its ventral fiber group and the ischiocavernosus muscle form a functional and morphological unity. While the bulbospongiosus muscle and the external anal sphincter remain independent muscles, their frequent connection might have clinical implications for perineal surgery and anogenital disorders.

Anatomy of sex: Revision of the new anatomical terms used for the clitoris and the female orgasm by sexologists.

Sexual medicine experts and sexologists must spread certainties on the biological basis of the female orgasm to all women, not hypotheses or personal opinions. Therefore, they must use scientific anatomical terminology. The anatomy of the clitoris and the female orgasm are described in textbooks, but some researchers have proposed a new anatomical terminology for the sexual response in women. The internal/inner clitoris does not exist: the entire clitoris is an external organ. The clitoris is not composed of two arcs but of the glans, body, and crura or roots. "Clitoral bulbs" is an incorrect term from an embryological and anatomical viewpoint: the correct term is "vestibular bulbs." The bulbocavernosus muscles are implicated in inferior vaginismus, while the pubovaginal muscle is responsible for superior vaginismus. The clitoral or clitoris-urethro-vaginal complex has no embryological, anatomical and physiological support: the vagina has no anatomical relationship with the clitoris, and the clitoris is a perineal organ while the supposed G-spot is in the pelvic urethra. G-spot/vaginal/clitoral orgasm, vaginally activated orgasm, and clitorally activated orgasm, are incorrect terms: like "male orgasm," "female orgasm" is the correct term. The "vaginal" orgasm that some women report is always caused by the surrounding erectile organs (triggers of female orgasm). The male penis cannot come in contact with the venous plexus of Kobelt or with the clitoris during vaginal intercourse. Also, female ejaculation, premature ejaculation, persistent genital arousal disorder (PGAD), periurethral glans, vaginal-cervical genitosensory component of the vagus nerve, and G-spot amplification, are terms without scientific basis. Female sexual satisfaction is based on orgasm and resolution: in all women, orgasm is always possible if the female erectile organs, i.e. the female penis, are effectively stimulated during masturbation, cunnilingus, partner masturbation, or during vaginal/anal intercourse if the clitoris is simply stimulated with a finger. Clin. Anat. 28:293-304, 2015. © 2014 Wiley Periodicals, Inc.

Huperzia saururus Lam. Trevis. (Lycopodiaceae) facilitates ejaculation in spinal cord transected male rats

Ethnopharmacological relevanceHuperzia saururus (Lam.) Trevis. has an extensive ethnopharmacological use, mainly because of its aphrodisiac properties. The species is consumed as decoctions or infusions in traditional medicine. The purpose of the present research was to determine if Huperzia saururus is able to increase sexual potency by evaluating the ejaculatory response, in the presence of a decoction in spinal cord transected male rats. Materials and methodsThe fictive ejaculation model to record the rhythmic contractions of the bulbospongiosus muscles that accompany ejaculation as an indicator of ejaculation occurrence was used. Sexually experienced male Wistar rats were used. The activation of the fictive ejaculation by the i.v. administration of a decoction was tested, as well as the effects of the oxytocinergic, cholinergic, adrenergic and nitrergic antagonism upon the pro-ejaculatory activity of Huperzia saururus. ResultsDecoction (3µg/animal) was able to activate the fictive ejaculation in spinal male rats, producing a statistically significant diminution on the latency of discharge parameter and a statistically significant augment for the number of discharges. Moreover, when sequential treatments using antagonists plus decoction were administered, the effects produced showed that prazosin prevent the pro-ejaculatory effect of the decoction and that the four antagonists assayed blocked the facilitatory effect of Huperzia saururus since the facilitation in the latency of response was prevented, and the number of discharges was reduced. Together these findings support the notion that the decoction exerts an aphrodisiac effect influencing the ejaculatory potency which is partially mediated by oxytocinergic, cholinergic, adrenergic and nitrergic spinal mechanisms. ConclusionIn agreement to the ethnopharmacological uses, Huperzia saururus decoction has aphrodisiac properties by influence on the ejaculatory potency.

Delay of ejaculation induced by Bersama engleriana in nicotinamide/streptozotocin-induced type 2 diabetic rats.

To evaluate the effects of aqueous and methanolic extracts of Bersama engleriana (B. engleriana) leaves on the expulsion phase of fictive ejaculation in nicotinamide/streptozotocin-induced type 2 diabetic male rats. The electromyographic activity of the bulbospongiosus muscles was recorded in urethane anaesthetized, spinal cord transected rats receiving dopamine (0.1 μmol/L/kg) intravenously, in the absence or presence of aqueous and methanolic extracts of B. engleriana (2.5, 10, 50, 60, 75 mg/kg). In another experiment, the pro-ejaculatory effect of dopamine (0.1 μmol/L/kg, i.v.) was monitored in rats orally pre-treated with the aqueous and methanolic extracts (60 mg/kg) of B. engleriana for 1 or 4 weeks. Results of the study showed that the intravenous administration of B. engleriana did not provoke any contraction of the ejaculatory muscles whilst rhythmic and rapid contractions of the bulbospongiosus muscles accompanied sometimes by penis movement and expulsion of the urethral contents were recorded after dopamine application. The sequential treatment of animals with B. engleriana extracts (2.5-75.0 mg/kg) followed by dopamine (0.1 μmol/L/kg) resulted in a dose-dependent abolishment of the pro-ejaculatory response due to dopamine. However, in animals orally submitted to a daily gavage with B. engleriana extracts (60 mg/kg) for 1 or 4 weeks, the ejaculation stimulating effect of dopamine (0.1 μmol/L/kg) was significantly delayed (P<0.01) but not completely suppressed. Present findings suggest the involvement of dopaminergic system in the activity of B. engleriana and further support its aphrodisiac potentials due to sterols and saponins revealed in this plant.

Effect of botulinum-A toxin injection into bulbospongiosus muscle on ejaculation latency in male rats.

Premature ejaculation (PE) is the most common male sexual dysfunction. A variety of pharmacotherapeutic strategies have been employed to treat men suffering with lifelong PE. However, there are currently no pharmaceuticals approved by the U.S. Food and Drug Administration specifically designed for PE treatment. Given that the bulbospongiosus muscle is involved in the ejaculatory reflex in both humans and rodents and that local administration of botulinum-A can abolish muscle contractions, the current study examined the effect of injection of botulinum-A toxin into the bulbospongiosus muscle on the ejaculatory latency of male rats. After screening for normal sexual activity with sexually receptive female rats, 33 sexually experienced male Long-Evans rats (Harlan Laboratories, Indianapolis, IN, USA) underwent an additional four pretreatment sexual exposures over the course of the following week, during which all components of sexual behavior were video recorded by trained observers. On the day after their fourth experience, rats were anesthetized and received a single injection of either 0.5 unit (n = 11) or 1 unit (n = 11) of botulinum-A toxin or saline vehicle (n = 11). Botulinum-A toxin was dissolved in 0.1 mL of saline vehicle and injected bilaterally into the bulbospongiosus muscle by the percutaneous route. Beginning 2 days after treatment, sexual behaviors were reexamined over the course of the following week on four separate occasions. The latency to achieve ejaculation, and the frequencies and latencies of mounts and intromissions were video recorded by trained observers in a blinded fashion. Relative to pretreatment measurements, bilateral injection of saline vehicle into the bulbospongiosus muscle did not affect ejaculation latencies. However, rats treated with either 0.5 or 1 unit of botulinum-A toxin exhibited significantly longer latencies to achieve ejaculation relative to pretreatment performance. Of note, botulinum-A toxin did not affect the ability to achieve mounts, intromissions, or ejaculation. These results demonstrate that botulinum-A toxin injection into the bulbospongiosus muscle is a safe and effective treatment that extends ejaculatory latency in rats without affecting the ability to engage in sexual activity or achieve ejaculation. Further studies are required to evaluate this therapeutic concept in PE patients.

Dracaena arborea extracts delay the pro-ejaculatory effect of dopamine and oxytocin in spinal male rats.

Dracaena arborea is a medicinal plant with ethnopharmacological aphrodisiac reputation. In the present study, the effect of an intravenous administration of aqueous and ethanolic extracts from the dried roots of this plant on the ejaculatory pattern of spinal cord-transected and urethane-anaesthetized rats was investigated. In addition, the effects of these extracts were also determined on dopamine and oxytocin-induced ejaculation. Systemic administration of aqueous and ethanolic extracts (5, 20, 60, 100 mg kg(-1)) of D. arborea did not activate fictive ejaculation, whereas dopamine (0.1 μM kg(-1)) and oxytocin (0.5 UI kg(-1)) provoked ejaculation evidenced by the rhythmic contractions of the bulbospongiosus muscles accompanied with penile erection and sometimes with expulsion of the seminal plugs. Pretreatment of spinal rats with D. arborea extracts dose-dependently blocked the pro-ejaculatory activity of dopamine and oxytocin. In conclusion, the present study shows that the bioactive substances present in the extracts of D. arborea inhibit the activity of the bulbospongiosus muscles through the blockade of dopaminergic and oxytocinergic receptors in rats.

Nonmyocytic androgen receptor regulates the sexually dimorphic development of the embryonic bulbocavernosus muscle.

The bulbocavernosus (BC) is a sexually dimorphic muscle observed only in males. Androgen receptor knockout mouse studies show the loss of BC formation. This suggests that androgen signaling plays a vital role in its development. Androgen has been known to induce muscle hypertrophy through satellite cell activation and myonuclei accretion during muscle regeneration and growth. Whether the same mechanism is present during embryonic development is not yet elucidated. To identify the mechanism of sexual dimorphism during BC development, the timing of morphological differences was first established. It was revealed that the BC was morphologically different between male and female mice at embryonic day (E) 16.5. Differences in the myogenic process were detected at E15.5. The male BC possesses a higher number of proliferating undifferentiated myoblasts. To identify the role of androgen signaling in this process, muscle-specific androgen receptor (AR) mutation was introduced, which resulted in no observable phenotypes. Hence, the expression of AR in the BC was examined and found that the AR did not colocalize with any muscle markers such as Myogenic differentiation 1, Myogenin, and paired box transcription factor 7. It was revealed that the mesenchyme surrounding the BC expressed AR and the BC started to express AR at E15.5. AR mutation on the nonmyocytic cells using spalt-like transcription factor 1 (Sall1) Cre driver mouse was performed, which resulted in defective BC formation. It was revealed that the number of proliferating undifferentiated myoblasts was reduced in the Sall1 Cre:AR(L-/Y) mutant embryos, and the adult mutants were devoid of BC. The transition of myoblasts from proliferation to differentiation is mediated by cyclin-dependent kinase inhibitors. An increased expression of p21 was observed in the BC myoblast of the Sall1 Cre:AR(L-/Y) mutant and wild-type female. Altogether this study suggests that the nonmyocytic AR may paracrinely regulate the proliferation of myoblast possibly through inhibiting p21 expression in myoblasts of the BC.

Identification of CNS Neurons Innervating the Levator Ani and Ventral Bulbospongiosus Muscles in Male Rats

The pelvic striated muscles play an important role in mediating erections and ejaculation, and together these muscles compose a tightly coordinated neuromuscular system that is androgen sensitive and sexually dimorphic. To identify spinal and brains neurons involved in the control of the levator ani (LA) and bulbospongiosus (BS) in the male adult and preadolescent rat. Rats were anesthetized, and the transsynaptic retrograde tracer pseudorabies virus (PRV) was injected into the LA muscle of adults or the ventral BS muscle in 30-day-old rats. After 3-5 days rats were sacrificed, and PRV-labeled neurons in the spinal cords and brains were identified using immunohistochemistry. The presence of gastrin-releasing peptide (GRP) in the lumbar spinal neurons was examined. The location and number of PRV-labeled neurons in the spinal cord and brain and GRP colocalization in the lumbar spinal cord. PRV-labeled spinal interneurons were found distributed throughout T11-S1 of the spinal cord, subsequent to dorsal medial motoneuron infection. The majority of spinal interneurons were found in the lumbosacral spinal cord in the region of the dorsal gray commissure and parasympathetic preganglionic neurons. Preadolescent rats had more PRV-labeled spinal interneurons at L5-S1 where the motoneurons were located but relatively less spread rostrally in the spinal cord compared with adults. Lumbar spinothalmic neurons in medial gray of L3-L4 co-localized PRV and GRP. In the brain consistent labeling was seen in areas known to be involved in male sexual behavior including the ventrolateral medulla, hypothalamic paraventricular nucleus, and medial preoptic area. Common spinal and brain pathways project to the LA and BS muscles in the rat suggesting that these muscles act together to coordinate male sexual reflexes. Differences may exist in the amount of synaptic connections/neuronal pathways in adolescents compared with adults.

Rhythmic motor patterns accompanying ejaculation in spinal cord-transected male rats

A spinal pattern generator controls the ejaculatory response. Activation of this spinal generator elicits rhythmic motor patterns of the striated musculature that surrounds the genital tract that contributes to the expulsion of seminal secretions. In the present study, we elicited ejaculation in spinal cord-transected male rats by mechanically stimulating the urethra and registered rhythmic motor patterns in the cremasteric, iliopsoas and pubococcygeus muscles. The rhythmic motor activity recorded in these muscles was compared with that elicited in the bulbospongiosus muscles; the results revealed similarities in the motor parameters among all the muscles. Data of this study, showing the occurrence of rhythmic motor behaviour in the cremasteric, iliopsoas and pubococcygeus muscles during ejaculation, suggest that these muscles might be under the control of the spinal generator for ejaculation.

Dynamics of male pelvic floor muscle contraction observed with transperineal ultrasound imaging differ between voluntary and evoked coughs

Coughing provokes stress urinary incontinence, and voluntary coughs are employed clinically to assess pelvic floor dysfunction. Understanding urethral dynamics during coughing in men is limited, and it is unclear whether voluntary coughs are an appropriate surrogate for spontaneous coughs. We aimed to investigate the dynamics of urethral motion in continent men during voluntary and evoked coughs. Thirteen men (28-42 years) with no history of urological disorders volunteered to participate. Transperineal ultrasound (US) images were recorded and synchronized with measures of intraabdominal pressure (IAP), airflow, and abdominal/chest wall electromyography during voluntary coughs and coughs evoked by inhalation of nebulized capsaicin. Temporal and spatial aspects of urethral movement induced by contraction of the striated urethral sphincter (SUS), levator ani (LA), and bulbocavernosus (BC) muscles and mechanical aspects of cough generation were investigated. Results showed coughing involved complex urethral dynamics. Urethral motion implied SUS and BC shortening and LA lengthening during preparatory and expulsion phases. Evoked coughs resulted in greater IAP, greater bladder base descent (LA lengthening), and greater midurethral displacement (SUS shortening). The preparatory inspiration cough phase was shorter during evoked coughs, as was the latency between onset of midurethral displacement and expulsion. Maximum midurethral displacement coincided with maximal bladder base descent during voluntary cough, but followed it during evoked cough. The data revealed complex interaction between muscles involved in continence in men. Spatial and temporal differences in urethral dynamics and cough mechanics between cough types suggest that voluntary coughing may not adequately assess capacity of the continence mechanism.

Purse-string morphology of external anal sphincter revealed by novel imaging techniques

The external anal sphincter (EAS) may be injured in 25-35% of women during the first and subsequent vaginal childbirths and is likely the most common cause of anal incontinence. Since its first description almost 300 years ago, the EAS was believed to be a circular or a "donut-shaped" structure. Using three-dimensional transperineal ultrasound imaging, MRI, diffusion tensor imaging, and muscle fiber tracking, we delineated various components of the EAS and their muscle fiber directions. These novel imaging techniques suggest "purse-string" morphology, with "EAS muscles" crossing contralaterally in the perineal body to the contralateral transverse perineal (TP) and bulbospongiosus (BS) muscles, thus attaching the EAS to the pubic rami. Spin-tag MRI demonstrated purse-string action of the EAS muscle. Electromyography of TP/BS and EAS muscles revealed their simultaneous contraction and relaxation. Lidocaine injection into the TP/BS muscle significantly reduced anal canal pressure. These studies support purse-string morphology of the EAS to constrict/close the anal canal opening. Our findings have implications for the effect of episiotomy on anal closure function and the currently used surgical technique (overlapping sphincteroplasty) for EAS reconstructive surgery to treat anal incontinence.

Bulbocavernosus muscle area measurement: a novel method to assess androgenic activity

Serum testosterone does not correlate with androgen tissue activity, and it is critical to optimize tools to evaluate such activity in males. Ultrasound measurement of bulbocavernosus muscle (BCM) was used to assess the relationship between the number of CAG repeats (CAGn) in the androgen receptor (AR) and the BCM size; the changes in the number of CAGn over age were also evaluated. Transperineal ultrasound measurement of the BCM was also performed. AR CAGn were determined by high performance liquid chromatography, and morning hormone levels were determined using immunoassays. Forty-eight men had CAG repeat analysis. Twenty-five were <30 years of age, mean 23.7 years (s.d. = 3.24) and 23 were >45 years of age, mean 53 years (s.d. = 5.58). The median CAGn was 21 (13–29). BCM area was greater when the number of CAGn were <18 as compared to the number of CAGn >24 (P = 0.04). There was a linear correlation between the number of CAGn and the BCM area R2 = 16% (P = 0.01). In the 45 to 65-years-old group, a much stronger negative correlation (R2 = 29%, P = 0.01) was noticed. In the 19 to 29-years-old group, no such correlation was found (R2 = 4%, P = 0.36). In older men, the number of CAGn increased with age (R2 = 32%, P = 0.01). The number of CAGn in the AR correlates with the area of the BCM. Ultrasound assessment of the BCM is an effective surrogate to evaluate end-organ activity of androgens. The number of CAGn may increase with age.